From Embryo to a Cute baby…

Lying in one corner of my room was a female spider who had mated and laid eggs into a sac. I took those eggs and kept few in a cavity slide and sealed it, the remaining eggs still being inside the egg sac kept on a watch glass.
You can see how one egg appears to be under foldscope. This egg is about 3 days old. One can make out some movements of the developing embryo on the 4th day.

After about few days this is how the egg looked. Or rather the thing inside it looked. You can make out some structures which are going to become the legs of the spider in future.

A bit more clear in 1-2 days later… the movements (clearly it seems to be the beating heart of embryo.

Two eggs adjacent to each other

Embryo development and organ formation ended after a total of 10-12 days from the day of egg laying. The image below seems to show a fully formed spiderling still inside the egg. Amazing how the egg changed its shape to accomodate the spiderling.

The thing I missed to capture, was what was on the 14th day. On looking at the watch glass, I saw barely 2-3 spiderlings remaining. All of them soon after getting out of their eggs, ran off in random directions. I went straight to my foldscope to inspect the slide. This is what I observed.

The legs of the spiderlings, the abdomen were all covered in fine hair or setae. Eyes were eight in number (was left amazed when I saw this!)
A view of the head (and four of its legs). There is a line present on its head (or rather the head and the thorax together called as the cephalothorax). This line is significant as it helps the spiderling undergo ecdysis and escape from its old exoskeleton. It is the line of ecdysial cleavage, called dorsal ecdysial line.
The image appears blue because of a filter I used in my phone.
A bit curious about the how many eyes would be present, I observed the slide under a phase contrast microscope. At 200x, this is what I saw that left me amazed : ) Eight eyes; clusters of three were present on either side and two eyes present median in position.

I normally use this method to add water into the cavity. First of all take a dry cavity slide and coat the edges of cavity with a thin film of vaseline or paraffin wax. Then place the eggs right in the centre of the cavity. Now just take a drop of water and add to the cavity. Carefully slide a dry coverslip from one edge of slide over the cavity taking care that parts of the coverslip on the slide are stuck to the wax and are airtight. Slide it right upto 3/4 of the distance, leaving 1/4 uncovered. Now use a micropipette or a Pasteur pipette (or anything with a thin mouth), add water along the edge of coverslip into cavity and keep the slide vertical. Slowly slide coverslip and just seal the cavity totally airtight! This method minimises any air bubbles forming in the mount, and would have less interference with eggs too if you are careful enough.

Thank you SO much for such a detailed explanation! I think I’ll look into getting myself some cavity slides. I’ve been really into wet mount-ish kinds of samples and have tried spacing the cover slip from the slide with anything from tape to modeling clay. Tape worked well enough in the short term but with something so delicate it sounds like a cavity slide is exactly what I need!

From all the comments, you can already see the level of enthusiasm for your post. Fantastic work – absolutely brilliant. Thanks again for also sharing tips and tricks; and enabling others to be able to watch the microscopic world.

Absolutely inspirational post. Keep going – maybe you will catch the rest of the stages.. wouldn’t it be incredible to have all 14 days collapsed in 30 seconds 😉

Spider Eggs are easy to find. Walk in a grass field and turn the grass for the bottom side – you will see tiny patches of dense white “silk” like cacoon- each one of them have 100’s of spider eggs. Spider eggs are almost everywhere.

Fantastic post @Ronak. As Manu writes, it would be really great if you could compress 14 days of development into a 30 seconds video. I have always found that the second time I do something I have better ideas (hint hint). Also I remember Manu telling me that Spiders can survive many weeks in ziplock bags, so cavity slides wont be a big deal.